I agree with what everyone has said. You need to test your tank and see where you stand. It doesn't matter if you cycled the tank originally any time you add or take away something from the tank you disrupt its equilibrium thus disrupting the cycle. You have to do water changes to keep the oxygen from depleteing but still not take away so much water that you lose your cycle. Its always a bad idea to mess with the filter.. just take the cartridge out during water changes and then put it back in (always store it in a bowl or bucket of tank water).

Everytime you do a water change you should test the day before and the day after to make sure your readings don't swing too much. Adding new water can cause a swing in nitrates which could hurt your fish.

Do NOT keep putting in conditioner though, seriously. You should only use that stuff when you are doing a water change unless it states that it lowers the ammonia if its high.

Also, dont change your filter. When you do your water change, wash it off int he bucket of dirty water. All a filter does is get the stuff floating around in the water like small particles of food, dirt stirred up, and what not. This is how companies get you, your filter should last way over a month. Cut the carbon out of it and let it go. Its its a double layer filter, I recommend cutting the whole back piece off and dumping the carbon.

I just want to apologize. For some reason I only wrote that doesnt make any sense once but as I visit the site now I see it appeared numerous times. I did a full water change and cycled the tank using seachem stability. Thanks for the help.